There are three types of PV panel - all made from silicon cells. Monocrystalline panels are the most efficient, so unsurprisingly they are the most energy efficient. Polycrystalline panels are cheaper, yet less efficient.

The third type of PV panel - amorphous silicon - is less efficient still, but its flexibility makes it a valid option where installation of a solid panel isn't viable.

For example, if you have a curved roof or minimal flat surface area, amorphous PV panels could be ideal for your home.